Rotary circuit-controlling device



July 8, 1924.

c. w. BURGER ROTARY CIRCUIT CONTROLLING DEVICE Filed Feb- 20, 1922 2 Sheets-Sheet, 1

514m no 5,

July 8, 1924'. 1,500,603

C. W. BURGER ROTARY CIRCUIT CONTROLLING DEVICE File F 20, 1922 2 Sheets-Sheet 2 I 56 66 V 14M- 6. j 1/! 57 J0 r ii 7 y grfimrm W Patented July 8, 1924.

UNITED STATES PATENT OFFICE.

CLARENCE W. BURGER, OF WASHINGTON, DISTRICT OF COLUMBIA.

ROTARY CIRCUIT-CONTROLLING DEVICE.

To all whom it may concern:

Be it known that I, CLARENCE IV. BURGER, a citizen of the United States, residing at Washington, District of Columbia, have invented certain new and useful Improvements in Rotary Circuit-Controlling Devices, of,

which the following is a specification.

This invention relates to electric circuit controlling devices of that class wherein a contact finger or arm engages a rotary contact drum for the purpose of producing intermittent impulses.

The invention is particularly designed for use as a transmitter for producing telegraphic codes, such transmitters being commonly employed as an aid to those desiring to learn the art of-telegraphy. However, as will be readily understood, the invention may also be applicable to other uses, such for example as a sign flasher, etc.

Rotary circuit controlling devices of this general character have heretofore been proposed, but such devices have been of a more Or less complicated and expensive nature owing to the amount of machine work and careful adjustments which were necessary.

The primary object of the presentinvention is, therefore, to produce arotary circuit controlling device of the character referred to' which shall be exceptionally simple in construction and cheap to manufacture. To this end I propose to employ as the basis for my improved circuit controlling instrument, standard commercial clockwork such as may be purchased from any clock manufacturer. On this clockwork I propose to mount a removable contact drum journaled on one of the existing shafts of the clockwork and preferably held in position by gravity.

In ordertoregulate the speed at which the contact drum is driven, I make use of a centrifugal governor as usual, but an object of the present invention is to improve and simplify the construction of such governor. To this end, I propose to mount the governor between the movement plates of the clockwork in place of the usual escapement.

Further objects of the invention are to provide an improved contact arm and method of mounting and automatically shifting the same so as tovary the sequence of electrical impulses transmitted, all as will hereinafter appear.

In order that the invention may be readily understood, reference is had to the accompanying drawings forming part of this specification, and in which:

Figure 1 is a plan view of my improved circuit controlling device or transmitter as it appears when in use;

Figure 2 is an end elevation thereof;

Figure 3 is a vertical section'on the line 3-3 of Figure 1, parts being shown in elevation;

Figure 4 is a vertical section on the line 44 of Figure 1, parts being omitted for the sake of clearness Figure 5 is a vertical section on an enlarged scale through a fragment of the contact drum, the contact arm and the controlling means therefor;

Figure 6 is a fragmentary sectional plan on an enlarged scale showing the end of the contact arm which is in engagement with the drum;

Figure 7 is a vertical section on the line 77 of Figure 6 showing details of the contact arm and drum; and

Figure 8 is a perspective view of the controlling means for the contact arm.

Referring to the drawings in detail, my improved transmitting device includes stand ard clockwork comprising spaced movement plates 1 and 2, separated by spacing rods 4 i and held together by screws 5, as usual. I propose to utilize this clockwork with the movement plates in horizontal position, as shown.

In order to avoid the necessity of providing a base on which to mount the instrument, and thus save expense, I provide four supporting feet 6 secured to the corners of the lower plate 1 and preferably provided with pads or cushions 7 of soft rubber or the like.

In addition to the upper movement plate 2, and spaced therefrom by means of suitable spacers 4;, I provide a cover plate 3, co extensive with. the movement plates and preferably having one end thereof semicircular in shape, as indicated at 3! inFigure 1. This cover plate supports the contact arm hereinafter described and its associated mechanism. 7 V

Journaled in a. bearing bushing 8 set in the upper movement plate 2, and in a corresponding bearing in the lower plate 1 is a winding shaft 9 for the spring which drives the clockwork. Thisshaft 9 extends well above the upper movement plate 2 and its end is preferably squared, as indicated'at 10, to receive a winding key. The spring itself is indicated at 11, and as usual has its inner end secured to the shaft 9, while its outer end is anchored as at 12 to one of the rods 4. To the shaft 9 above the spring is secured a rigid wheel 13 with which engages a spring pressed pawl 14, such pawl being mounted upon the main driving gear 15, as usual, such gear being loose on the shaft 9. This main driving gear 15 meshes with a pinion 16 secured to a vertical shaft 17 journaled in the movement plates and extending above the upper plate 2. To the shaft 17 above the upper movement plate issecured a gear 18 and, between the two plates, a second gear 19. The gear 19 operates the train of gearing which drives the governor as will hereinafter be described more in detail, while the gear 18 drives the contact drum now'to be described.

This drum in its entirety comprises a gear 20 arranged to mesh with the gear 18, as shown in Figure 3, a hub 20 and a support- .ing plate 21, all rigidly secured together andhaving a tubular bearing member 22 extending therethrough. The upper portion of this bearing member 22 is somewhat enlarged, as shown, and its extreme upper end is hollowed out around the squared end 10 of the winding shaft, as indicated at 22 so as to accommodate the winding key. Mounted upon the plate 21 is the contact drum proper, comprising a series of flat metallic discs 23 of the same diameter as the plate 21, and provided with a central opening which fits over the bearing member 22. The set or group of superposed discs is clamped together by means of a clamping nut 24 threaded on to the upper end of the bearing member 22.

In order to properlyposition the several discs and prevent them from being assen bled with the wrong side uppermost (which would make the telegraphic code read backwards), I provide a positioning pin 25 set into the plate'21 and form in each disc a series of holes 26 any of which may be slipped over such pin in assembling the disc.

In addition to the holes 26, each disc is provided with a similar series of holes 27, arranged relative to the holes 26 in other than a radial relation. The holes 27 when the discs are assembled should of course be made to register, and this can only be done when ing formed in the cover plate 3 so as to permit the gear 29 to pass freely therethrough when the contact drum is removed or replaced. It will be observed that the contact drum is held in position on this vertical shaft by gravity and is supported by resting upon the bearing bushing 8.

The lower end 28 of the shifting pin or pins 28 extends below the plate 21, as shown in Figure 5, andsuch end is adapted to engage a star wheel 29 as the contact drum rotates. Thus the star wheel is shifted and advances equal to the space of one tooth every time a pin 28 passes it.

The star wheel 29 is secured to a drum 30 journaled on a screw 31 set into the cover plate 3. Surrounding the drum 30 and rigid therewith is an annular cam member 32 having around its upper edge a series of steps 32, as shown best in Figure 8. This cam member 32 is preferably formed as a flat plate, for ease in manufacture, and is then bent around the drum and secured 37 set into the cover plate 3, whereby thebracket and arm are also capable of swinging in a horizontal plane. The free end of the contact arm bears against the'contact drum above described, and is yieldinglyheld in engagement therewith by means of a spring 38 coiled around the screw 37'. One

end 38 of the spring engages a fixed pin 39 in the cover plate, while the other end 40 is bent over into engagement with the arm 34 as indicated at 41.

The outer end of the arm 34 which bears against the contact drum carries a contact pin in the form of a screw 42 having afrom slightly beyond the inner surface of the arm 34, as clearly shown in'Figures 6 and 7. whereby such tapered point engages the edge of the discs constituting the contact By reference to Figure 6, it will be drum. seen that the edges of these discs are milled or otherwise formed so as to provide teeth of greater or less width. When the instrument 1s used as a telegraphic transmitter the teeth on the discs will correspond to the dots and dashes of the telegraphic code in the usual manner. It will be noted however,

that the arrangement of contact pin relative to the arm 34 and discs 23 is such that the extreme end of the pin touches the projecting teeth as the disc revolves, thus making the desired electrical contact, but is not permitted to dro down into the spaces between the teeth. T is is due to the fact that the inner face of the contact arm, which, as above stated, is of insulating material, rides upon the contacts or teeth and prevents the pin from dropping into the notches or spaces between them. Thus durin the interval between one tooth and anot er the electric circuit is interrupted, and it is closed only during the actual engagement of the point 43 of the pin with a tooth.

By means of the above described con struction of contact arm and pin I am enabled to obtain a perfectly smooth running and effectively operating contact drum without the necessity of filling the spaces or notches between the contact teeth with insulating material as is usual in apparatus of this character. Not only does this cheapen the construction of the contact drum, but it permits the disks to be readily assembled in different combinations and different order, as desired.

The point 43 of the contact pin or screw is of less diameter than the thickness of the discs 23, as clearly shown in Figure 7 and although these discs are in close contact with each other, it is thus possible to shift the arm 34 so as to bring the contact pin selectively into engagement with any desired disc. In this connection it will of course be understood that each of the discs preferably has the teeth arranged to form a different telegraphic message or series of characters, and it is of course desirable that the learner should be given the benefit of all of the different signals or messages Moreover, it is desirable that the contact arm be shifted from one disc to another automatically and irregularly, so as to vary the message being transmitted and to keep the learner in ignorance of what particular message to expect.

This automatic'shifting of the contact arm to vary the sequence of the signals being transmitted is effected by the rotation of'the star wheel 29 by the pins 28, any desired number of which may be employed. Each time that a pin 28 passes the star'wheel the stud 23 will be caused to move from one stop of the cam to the next, thus shifting the contact pin or screw 42 from engagement with one disc into engagement with another. The height of the steps of the cam, and the length of the contact arm are so proportioned that at each step the contact pin 42 will be shifted a distance equal to the thickness of one disc. Thus, without insulating or spacing the discs from each other it is possible to selectively engage them with the contact pin. This results in an exceedingly simple structure, both mechanically and electrically considered.

The electrical circuit is connected with the contact pin 42, preferably by means of a metallic strip 45 secured to the arm 44 adjacent the contact pin 42 and connectedwith a flexible lead 46, the other end of which is preferably secured to a binding post 47 supported by the cover plate 3, but insulated therefrom by means of an insulating bushing 47. A second binding post 48 is provided and secured directly to the cover plate 3. Thus the only parts which are insulated are the binding posts 47 and contact screw 42. All of the other parts of the instrument are grounded.

In using the device a conductor 49 is connected to the binding posts 47 and 48 to form a loop which includes a battery 50 and a suitable buzzer or the like 51.

In order to regulate the speed at which the contact drum is driven, I provide an improved and simplified centrifugal governor. This governor is mounted upon a vertical shaft 54 journaled at its ends in the movement plates 1 and 2 at the points where the escapement is usually located in ordinary clockwork. To the shaft 54 is secured a pinion 53 which meshes with a gear 52 driven by a train of gearing from the gear 19 above described. Loosely mounted on the shaft 54 near its upper end is a disc 55 and to this disc is pivoted a pair of arm 56. Links 57 pivotally connect the middle point of these arms to a yoke 58 rigidly secured to the shaft 54 near its lower end, and a spring 59 surrounds the shaft 54 and yieldingly supports the disc 55. Thus when the shaft 54 is rotated by the gearing described, the governor is caused to revolve and the arms 56 fly outward, thus drawing down the disc 55 against the tension of the spring 59.

Arranged toengage underneath the edge of the disc 55 is a brake shoe 60 carried by a resilient strip 61 secured at 62 to the movement plate 2. A thumb screw 63 works through the cover plate 3 and bears against the strip 61, and it will thus be obvious that by adjusting this screw the brake shoe 60 may be raised or lowered, thus regulating the speed of the governor and consequently the speed of the contact drum.

From the above, therefore, it will be seen that I take a commercial clockwork and superpose upon the movement plates a cover or supporting plate on which my improved contact mechanism is mounted. It will also be noted'that no extra shaft or support is required for the contact drum and that the governor is mounted between the move ment platesthe same as the rest of the clockwork, thus producing an exceptionally cheap, compact and effective arrangement.

I cla1m:

1. In a device'of the class described, the combination with aspring motor comprising spaced movement plates and clockwork hav ing shafts extending outside of said plates,

of a contact drum andgear rigidly attached thereto loosely mounted on said shaft and bodily removable therefrom, without disturbing any of the other parts, said gear, whenthe drum is in operative position, being in mesh with one of the clockwork gears.

2. In a device of the class described, the combination with a spring motor, comprising spaced movement plates, and clockwork having shafts journaled in said plates, one of said shafts projecting beyond one of the plates, of a contact drum, and gear rigidly attached thereto, loosely mounted on said shaft and bodily removable therefrom together, without disturbing any other parts of the mechanism, and means whereby, when the drum is in operative position, said gear is driven by said clockwork.

8. In a device of the class described, the combination with a spring motor, comprising spaced movement plates,and clockwork having shafts journaled in said plates, two of said shafts projecting beyond one of said plates, of a gear rigidly secured to the end of one projecting shaft,'a contact drum and rigidly attached gear loosely mounted on the other projecting shaft, and bodily removable therefrom, without disturbing any other. parts of the mechanism, said two gears being in mesh when the drum is in operative position.

4. In a device of the class described, the combination with a springmotor comprising horizontal spaced movement plates and clockwork journaled in said plates, of a shaft projecting vertically upward above the upper of said plates, 2. horizontal contact drum journaled on said shaft and held in position by gravity, and means for driving said drum from the spring motor.

5. In a device of the class described, the

combination with a spring motor comprising spaced movement plates and a cover plate spaced therefrom, of clockwork mounted between said movement plates and having a shaft projecting up through the upper movement plate and the cover plate, said cover plate having an enlarged opening around said. shaft, and a contact drum havin a gear rigidly attached thereto journfl ed on said shaft and removable therefrom, said gear being movable through said opening into and out of mesh with a gear of the clockwork. j

i 6. In a device of the class described, the combination with a spring motor comprising spaced movement plates and clockwork journaled therein, of a contact drum driven by said clockwork, and a centrifugal governor for regulating the speed of said drum, said governor comprising a shaft journaled in the movement plates parallel with the shafts of said clockwork, and'driven by such clockwork.

7. In a device of the class described, the

combination with a spring motor comprising spaced movement plates and clockwork journaled therein, of a contact drum driven by said clockwork, and a centrifugal governor including an adjustable brake shoe for regulating the speed of said drum, said governor being located between the movement plates and driven by the clockwork, and a set screw extending through one of said movement plates for adjusting said brake shoe.

9. In a device of the class described,the combination with a spring motor comprising horizontal spaced movement plates with clockwork mounted between them, of a centrifugalgovernor also located between said plates and comprisinga vertical shaft journaled in said plates and driven by the clock-- work.

10. In a device of the class described, the combination with a contact drum having a plurality of annular rows of contacts, of a contact arm of insulated material having a contact pin extending therethrough and adapted to bear against said drum, and means for shifting saidarm to cause said pin to selectively engage any desired one of said rows of contacts.

11. In a device of the class described, the combination with a contactdrum having a plurality of annular rows of contacts, of a pivoted contact arm of insulated material having a contact pin set therein, a rotary cam for swinging said arm on its pivotto cause saidpin to engage different rows of contacts, and means operated by the rotation of said drum for shifting said cam.

12. In a device of the class described, a contact drum comprising an assembled series of metallic discs in close contact with each other, a contact arm having means to engage. the edges of said discs, and means to shift said contact arm step by step a distance equal to the thickness of a disc so as to cause said arm to engage first one disc and then another.

13. In a device of the class described, the

combination with a contact drum comprising an assembled series of metallic discs in close contact with each other, av contact arm having means to engage the edges of said discs, and automatic means operated by the rotation of said drum for shifting said contact arm step by step so as to'cause it to successively engage one disc after another. 14. In a device of the class described, the

said contacts having notches or spaces between them, of an arm having a face of insulating material, a contact pin carried by and extending through said arm with its point projecting slightly beyond said face and arranged to engage said contact-s, whereby said face rides upon the contacts when the pin is passing from one to another, and prevents the point of said pin from dropping down into the notches or spaces between the contacts.

In testimony whereof I affix my signature.

CLARENCE W. BURGER. 

